METHOD OF DRILLING HOLE FOR FOUNDATION PILE SUCH AS IN-SITU PILE OR THE LIKE AND DEVICE THEREFOR

摘要

PURPOSE:To strengthen the peripheral surface support force by setting and press-fitting a casing provided in its outer peripheral section with a horizontally pressing device, in a hole which is drilled in the ground by a digger, and by pressing the inner surface of the drilled hole with the use of the horizontally pressing device so as to form the inner surface of the drilled hole in the ground in an optional shape. CONSTITUTION:A horizontally pressing device S1 having a double pipe structure which is split into a plurality of sections is formed in the outer peripheral section of the casing 1, and a press frame 5 is extended and retracted horizontally by a horizontal cylinder 3. Further, a downward pressing device S2 is provided below the device S1, and a downward pressing frame 8 is extended and retracted vertically by a vertical cylinder 4. Then, a hole is drilled in the ground by a digger K, and the casing 1 is set and press-fitted in the hole while the frame 5 being extended toward the outer periphery by the cylinder 3 so as to press the inner wall of the hole in the ground, and these steps are repeated up to a predetermined depth. The frame 8 is lowered by the cylinder 4 in the device S2 so as to press and strengthen the ground at the bottom end of the hole. Accordingly, it is possible to strengthen the peripheral surface support force.